Okay, let's tackle this math problem. We're starting with 768142 and subtracting 36543.

Step 1: We'll start by subtracting the digit 3 and the borrow 0 from 2 in column 1 and get -1.
We add -1 to 10 and get 9 as the first digit of the result.

Step 2: We'll start by subtracting the digit 4 and the borrow 1 from 4 in column 2 and get -1.
We add -1 to 10 and get 9 as the next digit of the result.

Step 3: We'll start by subtracting the digit 5 and the borrow 1 from 1 in column 3 and get -5.
We add -5 to 10 and get 5 as the next digit of the result.

Step 4: We'll start by subtracting the digit 6 and the borrow 1 from 8 in column 4 and get 1.
1 is the next digit of our result.

Step 5: We'll start by subtracting the digit 3 and the borrow 0 from 6 in column 5 and get 3.
3 is the next digit of our result.

Step 6: We'll start by subtracting the digit 0 and the borrow 0 from 7 in column 6 and get 7.
7 is the next digit of our result.

So, 768142 - 36543 = 731599.